This chart shows both the mortgage debt-to-income ratio (which is still declining from the peak) and the house price-to-rent ratio (which is climbing back up). Here you go:

Here’s the explanation:

Figure 2 plots the house price-to-rent ratio and the mortgage debt-to-income ratio, each normalized to 100at its pre-recession peak. The price-to-rent ratio (red line) reached an all-time high in early 2006, marking the apex of the housing bubble. Currently, the price-to-rent ratio is about 25% below the bubble peak. As house prices have recovered since 2011, so too has rent growth, providing some fundamental justification for the upward price movement

The mortgage debt-to-income ratio(blue line) reached an all-time high in late 2007, coinciding with the peak of the business cycle. An important lesson from history is that bubbles can be extraordinarily costly when accompanied by significant increases in borrowing. On this point, Irving Fisher (1933, p. 341) famously remarked,“over-investment and over-speculation are often important; but they would have far less serious results were they not conducted with borrowed money.

The authors are making the argument that this time debt isn’t playing as large a part in the housing market rebound, because it’s simultaneously becoming more expensive to rent. They end with a note of caution about not wanting to repeat the mistakes of the past, and overly-fuel housing prices.

I just think it should be cheaper to rent! The Twin Cities market is still quite tight. (Not compared to San Francisco, though.)